Case Study: Restoring Implants With Digital Impressions

Case Study: Restoring Implants With Digital Impressions
Monday, April 15, 2013

Digital Impressions are certainly not something new or just a passing fad. In fact, at Ziemek Laboratories we’ve been working with digital impressions for years and have managed more than 30,000 digital impression cases for dentists from all around the country.

In this case study I will outline how this technology is now being used with the iTero scanner from Align Technologies to restore Straumann implant cases and demonstrate how the digital implant impression is captured, how custom abutments are designed and fabricated from the digital scan, and how the restorations are fabricated and seated without using a traditional PVS impression.

Up to this point in time the majority of digital impression cases completed at Ziemek Laboratories have been crown and bridge applications for prepped teeth. In other words, we received the digital scan file from either a 3M ESPE 3M C.O.S. or 3M True Definition Scanner, an iTero, or the CEREC from Sirona, and we used the information captured in the digital impression to fabricate virtually any type of fixed restoration imaginable from all the materials on the market today be it alloy, zirconia, lithium disilicate or composite.  A newer application for digital scanners is to scan implants, accurately capturing their position, and then using that digital information to accurately design and fabricate custom abutments and restorations.

Early on—and for some still to this day—a dentist digitally scanning his or her crown and bridge impressions would still have to use a traditional PVS impression to capture an implant, as the technology to capture an implant impression digitally had not been perfected. This era is coming to an end with partnerships between some of the major implant companies and the digital scanner manufacturers. 

At Ziemek Laboratories our first experiences working with digital implant impressions took place a couple of years ago with the BIOMET 3i Encode platform and the iTero scanner. Those familiar with the 3i Encode system know that instead of placing an implant impression pick-up or transfer coping into the implant in the mouth and capturing it in a PVS impression, you instead take an impression of the Encode healing cap that has special indentations on it which provide the precise information required for 3i to determine the implant position, design an encode custom abutment, and place the analog in the model.

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Figure 1: The implant with the scan locator in place, ready for the digital impression.

In this workflow, the dental lab fabricates a stone model from the dentist’s impression of the Encode healing cap and sends it to 3i. 3i places the analog in the model and designs and mills a custom abutment which is sent back to the lab to fabricate the restoration.

In the next phase, 3i and Cadent formed a partnership in 2011 allowing iTero users to scan the 3i encode healing cap instead of capturing it via a traditional PVS impression. Then a resin model was fabricated by Cadent with the precise location of the analog built into it. This eliminated the step of the dental lab fabricating a stone model and sending it off. The custom abutment is designed and fabricated from the digital scan. The lab receives the resin model with the analog and the custom abutment, and fabricates the restoration.

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Figure 2: The digital impression of the implant with the scan locator in place.

While it was a great step forward for iTero users to be able to digitally scan this type of implant instead of using a traditional PVS impression, it restricted them to not only 3i as the implant manufacturer, but specifically only to the Encode implant system. Fast forward one year when Align and Straumann announced a partnership wherein iTero users can now digitally scan Straumann implants and receive authentic Straumann custom abutments with their restorations.

In this application, illustrated here with pictures from an actual Ziemek Laboratories case, the dentist removes the healing cap and places a Straumann scan locator into the implant (Figure 1) and then scans the locator with their iTero scanner and sends the file to the lab (Figure 2). The scan locator provides the precise orientation and position of the implant.

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Figure 3: The digital design of the custom implant abutment.

Ziemek Laboratories, working with the Straumann CARES scanner and Straumann CARES custom abutment design software, receives the file and sends it off to iTero for resin model fabrication while simultaneously designing the Authentic Straumann custom abutment, sending that file to Straumann for the abutment fabrication in the dentist’s choice of either titanium or zirconia—in this case it was titanium (Figure 3).

The workflow allows multiple steps to be handled at the same time, speeding up production without compromising accuracy.

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Figure 4: The custom abutment on the model.

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Figure 5: The crown on the model.

The lab receives the custom abutment and model and fabricates the restoration of choice. In this case it was an e.max Press #3 (Figures 4 & 5). After the implant is properly healed, the dentist places the custom abutment and the corresponding restoration (Figures 6 & 7).

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Figure 6: The custom abutment is placed.

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Figure 7: The finished restoration.

The original partnership between Straumann and Cadent had Straumann as not only a partner in the technology used in the case I just presented, but also as a distributor of iTero scanners. When the distribution partnership was ended last fall, I believe the fine print was lost on consumers. This announcement meant Straumann is no longer selling and servicing the iTero, which in my opinion is a good thing as it is my experience that technology support is often much better when buying directly from the manufacturer.

However, following the news that the distribution agreement was ending, I have had many dentists tell me they didn’t believe the workflow I just outlined was possible after the companies parted ways. Of course that is not the case. The fact of the matter is that this application is still entirely alive and well. The system is extremely accurate and streamlines the workflow in our lab while allowing us to provide Authentic Straumann custom abutments and restorations for our clients and their patients. These restorations look and fit beautifully, and both Straumann and Align are absolutely fabulous to work with on these cases.

I was recently informed by a rep from Straumann that they are now live and operational with this workflow in Europe with the 3M True Definition Scanner, and they expect the 3M True Definition Scanners in the U.S. to add this functionality in the next couple of months. Very soon owners of both the iTero and 3M True Def scanner will be able to scan Straumann implant cases digitally instead of taking a traditional PVS impression.

The digital workflow between the dental clinic and the dental lab, and the digital evolution of our industry is now undeniable. For anyone in the dental field it’s simply a matter of when—not if—the technology available will provide everyone with the same benefits that we, along with our dental clients have been enjoying and utilizing for years at Ziemek Laboratories. 

All photos courtesy of Ziemek Laboratories and Dr. Mark Germack, DDS.

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